DE102013108215A1 - Transparent protective layer arrangement of an optically active layer system, IR-reflecting layer system and method for its production - Google Patents

Abstract

The invention relates to a protective layer arrangement of an optically active layer system arranged on a substrate S, which is formed from transparent metal, mixed metal or semiconductor compounds. The invention also relates to an IR-reflecting layer system with such a protective layer arrangement SA and to a method for producing a layer system. In order to improve the mechanical resistance of the various known layer systems, while maintaining their optical properties, the protective layer arrangement SA is formed as a mixed layer which viewed from the substrate S upwards, comprising a region of a silicon oxynitride and above a region of a silicon nitride.

Description

The invention relates to a protective layer arrangement for an optically effective layer system, which is arranged above the uppermost functional layer of the layer system and in particular serves for the mechanical protection of the layer system. The invention also relates to a transparent, infrared radiation (IR) -reflecting layer system using such a protective layer arrangement and to methods for producing the layer systems.

Different functional layer systems are known for the most diverse applications which, as an optically effective layer system, influence incident light in different ways and usually depending on the wavelength, i. reflect, absorb or pass through. Depending on the field of application, these layer systems can therefore be transparent, partially transparent or non-transparent. By way of example, transparent IR-reflective layer systems or highly reflective systems, e.g. in the visible spectral range and near infrared range for thermal barrier coatings or in the visible range for surface finishes.

Such layer systems usually have a complex system of individual layers, which are matched in their connection with each other to the required physical and chemical requirements of the layer system. In general, an optically active layer system, viewed from the substrate upwards, first comprises a base layer arrangement, one or more functional layer arrangements and a cover layer arrangement.

The term "basic, functional or covering" layer arrangement "as a rule comprises more than one layer, but also includes that a layer arrangement consists only of a single layer, which realizes the respective function. The assignment of individual layers to the basic, functional, covering or further layer arrangement is not always unambiguous, since each layer has an influence on both the adjacent layers and on the entire system. Generally, a layer is assigned based on its function.

In particular, a basecoat arrangement serves to adhere the system to the glass, chemical and / or mechanical resistance, and / or adjustment of optical properties of the system, e.g. the color or the reflection.

Overlying the base layer arrangement is a functional layer arrangement comprising one or more functional layers. The functional layer is generally the layer or layers which have the decisive property of the optically effective layer system for the respective application. The functional layer arrangement optionally comprises further layers which support this function and which can allow influencing their optical, chemical, mechanical and electrical properties.

An IR-reflecting layer system, referred to as an example of an optically active layer system and subsequently also only as a layer system, is functionally characterized by its low emissivity and associated high reflectivity and low transmission in the spectral IR range (wavelengths of >> 3μm). At the same time, a high transmission in the visible light range is often to be achieved. It thus has a steep drop in transmission and a large increase in reflection in the transition from visible light to near infrared. Due to their low emission behavior, such layer systems are also referred to as low-E layer systems.

Functional layers of an IR-reflecting layer system consist of a noble metal or alloys thereof, usually silver. This material has high reflectivity even at low layer thicknesses, especially in the infrared range, combined with low absorption in the visible spectral range of the light.

Alternatively, other materials such as copper or alloys thereof are used. These materials in turn require adaptation of the remaining layers belonging to the layer system. The additional layers of the functional layer arrangement include, in particular, blocking layers which prevent or at least significantly reduce diffusion and migration processes in the functional layer.

At the top, an optically effective layer system is completed by a cover layer arrangement. This serves for the anti-reflection and / or the mechanical and chemical protection of the layer system. The cover layer arrangement usually consists of one or more layers of a dielectric oxide or nitride or oxynitride of a metal and / or a metal mixture and / or a semiconductor. These dielectric materials are considered as non-absorbent materials, which qualifies them for the described optical function.

The antireflection coating is regularly produced by destructive interference, the optical thickness (product of layer thickness and refractive index of the layer) of individual or a series of antireflection coatings being dimensioned such that portions of the refractive index reflected at the respective boundary surfaces extinguish incident light by interference. As a result, it is possible, if appropriate also in conjunction with an antireflective basecoat, to increase the transmission of the overall system.

For the cover layer arrangement of numerous optically active layer systems, in the case of more than one layer, materials with varying refractive index are frequently used. The latter is known as a high-low cover layer arrangement, with "high-low" the change of high and low refractive materials is designated. In the case of transparent layer systems, high-refractive index materials are generally transparent materials whose refractive index is in the range from 1.8 to 2.7, in most cases even in the range of 1.9, preferably from 2.0 to 2.6. For comparison, the substrate, usually float glass, which has a low refractive index of about 1.52 on the other hand. Accordingly, materials having indexes of refraction in the region adjoining the high refractive index region at lower values and ranging to 1.5 or a few tenths below are regarded as low refractive index. The transparent dielectric materials are considered as non-absorbent materials, which qualifies them for the described optical function.

The covering layer which closes off the optically effective layer system should also protect the layer system against mechanically or chemically induced changes. For this reason, the choice of material of the anti-reflective layers of the cover layer arrangement is made so that a material with higher mechanical and / or chemical strength is used as the uppermost layer. However, due to the desired anti-reflection effect, the choice of material depends on the remaining layers of the cover layer and in particular on the adjacent layer. This significantly limits the choice of material.

Frequently transparent metal or semiconductor compounds are used for the cover layer arrangement, in particular silicon nitride, which is to be expected according to the above description of the high refractive index materials. While the relatively dense silicon nitride provides good mechanical and chemical protection, scratch resistance has been found to be insufficient for large scale industrial processing. In addition, the usable layer thickness and thus its protective effect of silicon nitride is limited due to the high optical efficiency associated with the high refractive index.

The deposition of the various optically effective layer systems often takes place by means of sputtering, which enables the production of suitable individual layers even with only very small layer thicknesses, whose composition and properties can be set very well and reproducibly by means of the target materials, the type of sputtering and the sputtering parameters.

Optically effective, in particular IR-reflecting layer systems are frequently subjected to different heat treatments, e.g. Tempering processes for curing and / or deformation of the coated substrate. In this case, they have such a layer sequence with such layer properties, which make it possible to keep changes in the optical, mechanical and chemical properties of the layer system occurring during heat treatment within defined, narrow limits. Depending on the application of a coated substrate, its layer system is exposed to different climatic conditions in the annealing process in different time regimes.

It is an object of the invention to provide a protective layer arrangement for an optically active layer system, in particular for an IR-reflective layer system and a method for its production, which improves the mechanical resistance of the various known layer systems, while maintaining the achievable with the layer system optical properties, in particular its emissivity and transmission, and its color stability for annealing processes.

To achieve the object, a protective layer arrangement according to claim 1 and an IR-reflecting layer system using the protective layer arrangement according to claim 6 and a method for its production according to claim 10 are proposed. The respective dependent claims describe advantageous embodiments.

With the protective layer arrangement according to the invention, known layer systems can be modified, on the one hand without a relevant change in the optical performance of the layer system and, on the other hand, with existing coating systems without changing their system configuration.

As has been noted, with the formation of the protective layer assembly as a mixed layer of a series of silicon oxynitride and above, silicon nitride, i. the replacement of a portion of silicon nitride by silicon oxynitride a significant improvement in the mechanical resistance for the optically active layer system, in particular in the adhesion and the scratch resistance can be achieved. Due to the low to medium refractive index also reduces the optical efficiency, so that with the same optical thickness and higher film thicknesses can be used.

With high demands on the preservation of the optical properties of the optical layer system using such a protective layer arrangement over the previous system, it has proved advantageous that the thickness of the silicon oxynitride region is less than or equal to the thickness of the silicon nitride region.

It is irrelevant whether, for example, for target production or for reasons of optical and / or electrical properties, the mixed layer in one or more areas technologically related admixtures, such as aluminum, the target material often for this purpose in the order of 2% to about 10% is attached.

The achieved effect in mechanical resistance is achieved with the mixed layer for both a gradient layer and a mixed layers composed of partial layers. This makes it easier to adapt the method to the existing system configuration.

A simplification of the method and adaptability to an existing system configuration is also supported by a further embodiment of the invention, in which, when forming the mixed layer of partial layers, the partial layers directly adjoin one another.

It also proves to be advantageous if the protective layer arrangement according to the invention is also supplemented by a third sub-layer closing off the protective layer arrangement, which according to one embodiment of an oxide, nitrite, oxinitrite or oxicarbide of a metal, semiconductor, or a metal or semiconductor alloy is preferred made of titanium dioxide, and can further improve the abrasion resistance of the system.

The protective layer arrangement according to the invention can preferably be used instead of the previously known cover layer arrangements with the layer sequence of a metal or mixed metal oxide and silicon nitride or at least a part thereof for an IR-reflecting layer system. Such layer systems are often constructed very complexly with numerous individual layers for the optical properties and their protection in the production, temperature treatment and application, so that the replacement of the cover layer by the protective layer arrangement according to the invention has an immediate influence on the effectiveness of the production without sacrificing performance. According to the invention, the relatively dense silicon nitride can be used as the uppermost layer or uppermost region of the mixed layer, without, however, observing the associated mechanical stresses which frequently have led to flaking and consequential damage to the entire layer system in prior art layer systems.

It is also advantageous that the other constituents of the known optically active, for example, the IR-reflecting layer systems can continue to be used as before. In particular, it has been found for the latter that the protective layer arrangement also mechanically stabilizes a double-low E or a multi-low E layer system which has two or more functional layers with an intermediate layer arrangement between them.

The cover layer arrangement of an IR-reflecting layer system which is protected by the protective layer arrangement according to the invention may additionally comprise further cover layers also below the protective layer arrangement, for example for antireflection coating or an interface layer. Such a supplemental layer, which should be referred to as the lower cover layer here for distinction, may consist of a metal or mixed metal oxide.

For an IR-reflective layer system, the use of zinc stannate-containing interface layers for the relaxation and the antireflection coating is known to be advantageous. In connection with the protective layer arrangement according to the invention, it has proven to be advantageous for mechanical resistance to use a zinc stannate-containing layer as the lower cover layer. A comparable effect can also be achieved with a tin oxide-containing layer or a combination of the two. In the latter embodiment, the IR-reflecting layer system comprises two lower cover layers, one of which contains tin oxide and the other zinc stannate, wherein the zinc stannate-containing layer is, for example, over the tin oxide-containing layer.

To produce an optically effective layer system, the layers of the base layer arrangement and of the functional layer arrangement are deposited successively on a substrate by means of sputtering, for example by means of magnetron sputtering. Above the uppermost single layer of the uppermost functional layer arrangement, the mixed layer is likewise deposited by means of sputtering of at least two sputtering cathodes. For efficient deposition, for example in a continuous process, the known cathode configurations can be used. Often these are double magnetrons, of which one or two double magnetrons are used for the deposition of the protective layer arrangement according to the invention. Depending on the layer thickness and deposition rate to be achieved, the regions of the mixed layer can continue to be used be divided and a larger number of sputtering cathodes are used.

When using one or two double magnetrons, a silicon oxynitridic region is deposited by the first magnetron of the double magnetron arrangement or by the first magnetron or by several magnetrons, and subsequently by one or more magnetrons or double magnetrons a silicon nitridic region of the protective layer arrangement.

By means of a suitable system configuration and suitable design of the sputtering cathodes, the regions can be formed as partial layers with an oxygen and / or nitrogen content changed from one to the next partial layer or with oxygen and / or nitrogen content graded over the thickness of the protective layer arrangement. Those skilled in the art are well aware of suitable configurations of the sputtering devices for the fabrication of partial and gradient layers.

The deposition of the region of the protective layer arrangement preferably takes place by means of reactive sputtering with inflow of oxygen and / or nitrogen to the working gas. According to various embodiments of the reactive sputtering method, the oxinitridische portion of the protective layer assembly with an oxygen content in the process gas (working gas and reactive gas) is deposited, in which the oxygen flow into the coating device in the range of 0.1% to 50% of that nitrogen content, which for the deposition of nitridic Area of the protective layer arrangement is used and / or with a nitrogen content in the process gas, the gas flow is in the range of 50% to 100% of the nitrogen content for the nitridic region. Preferably, the oxygen influx is 0.1 to 25%, since in this area the advantages presented above are best developed and the sputtering process is more stable.

The invention will be explained in more detail with reference to embodiments. The accompanying drawing shows in

1 an IR-reflecting layer system with a functional layer and a protective layer arrangement according to the invention,

2 an IR-reflective layer system with a functional layer and an alternative embodiment of the protective layer arrangement according to the invention and

3 an IR-reflecting layer system with two functional layers and a protective layer arrangement according to the invention.

1 represents as IR-reflective layer system is a single-low E-layer system, in which over the one functional layer arrangement FA of the layer system with the insertion of a lower cover layer D1, the protective layer assembly SA is arranged.

• a) Grundschichtanordnung GA mit Si3N4, 25–30 nm, als einzige Grundschicht, alternativ auch TiO2 oder SnO2, oder zwei Grundschichten übereinander;
• b) eine Funktionsschichtanordnung FA aus – ZnO, 7–10 nm, als Keimschicht K, – Ag, 12–15 nm, als Funktionsschicht F und – eine Blockerschicht B aus einer Nickel und Chrom enthaltenden Verbindung oder einem unterstöchiometrischen Oxid, Nitrid oder Oxinitrid davon, im Ausführungsbeispiel: NiCrOx, 0,5–3 nm;
• c) eine Deckschichtanordnung DA aus einer unteren Deckschicht D1 aus Zinkstannat und der Schutzschichtanordnung SA aus zwei Teilschichten T1, T2, – ZnSnO3, 10–15 nm, als untere Deckschicht D1, – SiOxNy, 5–15 nm, als Teilschicht 1 T1, mit 0,1–25 % O2 im Reaktivgas und – Si3N4, 10–35 nm, als Teilschicht 2 T2, – wobei die Teilschichten T1, T2 auch Anteile von Aluminium aufweisen können.

On a washed substrate S made of 4 mm float glass, the following layers are applied by magnetron sputtering to produce the single-low E layer system:

• a) base layer arrangement GA with Si3N4, 25-30 nm, as single base layer, alternatively also TiO2 or SnO2, or two base layers on top of each other;
• b) a functional layer arrangement FA of - ZnO, 7-10 nm, as seed layer K, - Ag, 12-15 nm, as functional layer F and - a blocker layer B of a nickel and chromium-containing compound or a substoichiometric oxide, nitride or oxynitride thereof , in the embodiment: NiCrOx, 0.5-3 nm;
• c) a cover layer arrangement DA of a lower cover layer D1 of zinc stannate and the protective layer arrangement SA of two partial layers T1, T2, - ZnSnO3, 10-15 nm, as the lower cover layer D1, - SiOxNy, 5-15 nm, as a sub-layer 1 T1, with 0.1-25% O 2 in the reactive gas and - Si 3 N 4, 10-35 nm, as a sub-layer 2 T2, - where the sub-layers T1, T2 may also have proportions of aluminum.

Alternatively, instead of zinc stannate, the first cover layer D1 may also contain SnO 2 or both layers may be combined ( 2 ). The cover layer arrangement DA according to 2 further comprises a protective layer arrangement with three partial layers, wherein the third partial layer T3 opposite to the protective layer arrangement of 1 was added as the top layer of the layer system. It consists in this embodiment of TiO2 with a thickness in the range 2-5 nm. Alternatively, it may also consist of another oxide, nitride, oxynitride or oxicarbide of another metal, semiconductor or metal or semiconductor alloy.

The deposition of the protective layer arrangement SA takes place reactively by silicon targets, which may optionally have an aluminum content of 2 to 10%. The deposition takes place reactively in the presence of nitrogen or both gases, depending on the composition of the sub-layer. However, it is known that to stabilize reactive sputtering processes, nitrogen may also be added to the process gas to stabilize the process and without incorporating nitrogen into the layer. The third sub-layer T3 is reactively sputtered from a titanium target in the presence of oxygen.

• a) Grundschichtanordnung GA mit Si3N4, 10–30 nm, als einzige Grundschicht, alternativ auch TiO2 oder SnO2, oder zwei Grundschichten übereinander;
• b) erste Funktionsschichtanordnung FA1 aus – ZnO, 7–10 nm, als Keimschicht K, – Ag, 8–15 nm, als Funktionsschicht F und – eine Blockerschicht B aus einer Nickel und Chrom enthaltenden Verbindung oder einem unterstöchiometrischen Oxid, Nitrid oder Oxinitrid davon, z.B. NiCrOx 0,5–3 nm;
• c) ZNSnO3, 50–70 nm, als einzige Zwischenschicht der Zwischenschichtanordnung ZA;
• d) zweite Funktionsschichtanordnung FA2, wie zur ersten Funktionsschichtanordnung FA1 beschrieben;
• e) Deckschichtanordnung DA aus einer unteren Deckschicht D1 und einer Schutzschichtanordnung SA aus zwei Teilschichten T1, T2, – ZnSnO3, 10–15 nm, als untere Deckschicht D1, – SiOxNy, 5–15 nm, als Teilschicht 1 T1, mit 0,1–25 % O2 im Reaktivgas und – Si3N4, 10–45 nm, als Teilschicht 2 T2, – wobei die Teilschichten T1, T2 auch Anteile von Aluminium aufweisen können.

The layer system after 3 is different from that 1 by another, between functional layer arrangement FA and base layer arrangement GA according to 1 inserted functional layer arrangement. In the order from the substrate S upward, the lower functional layer is denoted by FA1 and the upper one by FA2. Both functional layer arrangements FA1 and FA2 are separated from each other by an intermediate layer arrangement ZA. This results in the following IR-reflecting layer system:

• a) base layer arrangement GA with Si3N4, 10-30 nm, as single base layer, alternatively also TiO2 or SnO2, or two base layers one above the other;
• b) first functional layer arrangement FA1 comprising - ZnO, 7-10 nm, as seed layer K, - Ag, 8-15 nm, as functional layer F and - a blocking layer B consisting of a nickel and chromium-containing compound or a substoichiometric oxide, nitride or oxynitride thereof , eg NiCrOx 0.5-3 nm;
• c) CNSnO3, 50-70 nm, as the only intermediate layer of the interlayer array ZA;
• d) second functional layer arrangement FA2, as described for the first functional layer arrangement FA1;
• e) cover layer arrangement DA consisting of a lower cover layer D1 and a protective layer arrangement SA of two partial layers T1, T2, ZnSnO3, 10-15 nm, as lower cover layer D1, SiOxNy, 5-15 nm, as partial layer T1, with 0.1 -25% O 2 in the reactive gas and - Si 3 N 4, 10-45 nm, as a sub-layer 2 T2, - wherein the sub-layers T1, T2 may also have proportions of aluminum.

Also the double low E layer system of 3 can be one or more of the too 2 having complementary layers described. The intermediate layer arrangement ZA can also consist of more than one layer.

LIST OF REFERENCE NUMBERS

• S

  substratum

  GA

  Base layer arrangement

  FA, FA1, FA2

  Functional layer arrangement

  ZA

  Interlayer arrangement

  SA

  Protective layer arrangement

  THERE

  overlay assembly

  K

  seed layer

  F

  functional layer

  B

  blocker layer

  T1, T2

  sublayer

  D1, D2

  topcoat

Claims (13)

Protective layer arrangement for an optically active layer system arranged on a substrate (S), which is formed from transparent metal, mixed metal or semiconductor compounds, characterized in that the protective layer arrangement (SA) is formed as a mixed layer, which looks upwards from the substrate (S) , an area comprising a silicon oxynitride and above a region comprising a silicon nitride. The protective layer arrangement according to claim 1, characterized in that the thickness of the region of the silicon oxynitride is equal to or smaller than the thickness of the region of the silicon nitride. Protective layer arrangement according to one of claims 1 or 2, characterized in that the mixed layer contains a gradient layer of said silicon compounds. Protective layer arrangement according to one of Claims 1 or 2, characterized in that the mixed layer contains two adjoining partial layers (T1, T2) of the said silicon compounds. Protective layer arrangement according to one of the preceding claims, characterized in that the protective layer arrangement (SA) comprises a third sub-layer (T3) terminating the layer system and consisting of an oxide, nitrite, oxinitrite or oxicarbide of a metal, semiconductor, or a metal or semiconductor alloy consists. IR-reflecting layer system which is arranged on a substrate (S) and, viewed from the substrate (S) upwards, comprises a base layer arrangement (GA) with at least one base layer and a functional layer arrangement (FA1, FA2) with at least one functional layer (F), characterized in that a protective layer arrangement (SA) according to one of the preceding claims is arranged above the functional layer arrangement (FA1, FA2). IR-reflecting layer system according to claim 6, characterized in that between the functional layer arrangement (FA) and the protective layer arrangement (SA) at least one lower cover layer (D1) is arranged, which consists of a metal or mixed metal oxide. An IR-reflecting layer system according to claim 7, characterized in that the one lower cover layer (D1) contains tin oxide or zinc stannate. IR-reflecting layer system according to claim 6 to 8, characterized in that between the base layer arrangement (GA) and the functional layer arrangement (FA1, FA2) at least one further functional layer arrangement (FA1, FA2) is arranged, wherein between two functional layer arrangements (FA1, FA2) a Interlayer arrangement (ZA) is arranged at least with an intermediate layer. Method for producing an optically effective layer system, wherein a base layer arrangement (GA) with at least one base layer and a functional layer arrangement (FA, FA1, FA2) with at least one functional layer (F) are deposited successively on a substrate (S) by sputtering, characterized a protective layer arrangement (SA) according to one of claims 1 to 5 is deposited over the functional layer arrangement. A method according to claim 10, wherein the protective layer arrangement (SA) is reactively deposited with the inflow of oxygen and / or nitrogen to the working gas, characterized in that the oxinitridische portion of the protective layer assembly (SA) is deposited with an oxygen content which is in the range of 0.1 % to 50% of that nitrogen content used to deposit the nitridic region of the protective layer assembly (SA). Method according to one of claims 10 or 11, characterized in that the oxinitridische portion of the protective layer assembly (SA) is deposited with a nitrogen content which is in the range of 50% to 100% of that nitrogen content, which is used for deposition of the nitridic region of the protective layer assembly (SA ) is used. Method according to one of claims 10 to 12, characterized in that as an optically active layer system, an IR-reflective layer system is deposited.

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